Endoscopic surgery is a significant method of performing surgical operations and has become the surgical procedure of choice due to its patient care advantages over “open surgery.” A particular type of endoscopic surgery is laparoscopic surgery. A significant advantage of laparoscopic surgery over open surgery is the decreased post-operative recovery time. In most instances, a patient is able to leave the hospital within hours after laparoscopic surgery has been performed, whereas with open surgery, a patient requires several days of hospital care to recover. Additionally, laparoscopic surgery achieves decreased incidents of post-operative abdominal adhesions, decreased post-operative pain, and enhanced cosmetic results.
Conventionally, a laparoscopic surgical procedure begins with the insufflation of the abdominal cavity with carbon dioxide. The introduction of this gas into the abdominal cavity lifts the abdominal wall away from the internal viscera. The abdominal wall is then pierced or penetrated with a device known as a trocar. A trocar includes a housing assembly, a cannula assembly attached to the housing assembly to form a bore through the trocar, and a piercing element called an obturator. The obturator slides through an access port formed on the upper end of the housing assembly and through the bore of the trocar. After insertion of the trocar through the abdominal wall of the patient, the obturator is removed by the surgeon while leaving the cannula protruding through the abdominal wall. The cannula may be fixed in place by using a fascia device, and laparoscopic instruments can then be inserted through the cannula to view internal organs and to perform surgical procedures.
Traditionally, the piercing tip of the obturator of a trocar has employed a sharp cutting blade to assist the surgeon in penetrating the abdominal wall. These obturators with cutting tips cut the tissue and muscle of the patient when inserted into the patient, and recovery time from the trauma of this cutting of tissue and muscle is necessary. Moreover, since the cutting tips are sharp, costly safety shield mechanisms are employed in trocars which operate to cover the obturator tip a short time after the obturator passes through the abdominal wall of the patient.
Unfortunately, such devices are not always effective. First, the external shield tends to provide an additional impediment to insertion, thus requiring greater incision force and compounding the risk of follow through injury. Second, the force of the safety shield passing through the skin tissue often results in tearing and other damage at the incision point. In addition to needlessly increasing the size of a surgical wound, this also tends to compromise the foundation of the cannula and may lead to undesirable leaks of fluids and gases during the operation. Third, many physicians complain that the recoil from the safety shield at almost the same moment as the trocar insertion tends to disorient them as to the precise location of the trocar after insertion. This results in wasted time and effort to reorient the trocar and greater risk of internal damage during the period of reorientation.
There remains a need for an obturator capable of piercing and separating tissue so as to lessen the risk of follow through injury.